Tailgate control system for round bale wagon

ABSTRACT

A control system for a tailgate on a round bale wagon is disclosed wherein the tailgate is maintained in an upright position to keep bales on the load bed of the vehicle until the forward end of the load bed has been raised sufficiently to impart enough energy to the bales to enable them to be more easily unloaded off the rearward end of the load bed. The control system includes an actuation mechanism that is engageable with the main frame upon the rotation of the load bed relative to the main frame to shift the spool of a control valve to permit hydraulic fluid to escape from the hydraulic cylinder operatively powering the movement of the tailgate to the upright position. The weight of the bales on the tailgate presents sufficient force to cause the tailgate to move to an extended position and, thereby, extend the ram from the hydraulic cylinder, forcing fluid from the cylinder. Movement of the load bed back to the home position, generally parallel to the main frame, causes the spring loaded actuation mechanism to operatively disengage from the main frame and effect a shifting of the control valve spool to permit fluid to flow back to the hydraulic cylinder and effect a retraction of the ram and movement of the tailgate back to the upright position.

BACKGROUND OF THE INVENTION

The present invention relates generally to vehicles for the handling ofmaterial or articles, which are self-loading or unloading and includessuccessive handling means, and, more particularly, to a tailgate controlsystem for a round bale wagon that maintains bales on the wagon untilthe load bed has been adequately rotated to impart sufficient energy tothe bales and permit them to be easily unloaded off the load bed.

The evolution of the hay industry in recent years indicates adiversification in baling, storing and transporting the hay with astrong trend toward using larger bales. Large round bales, varying inweight from about 800 pounds to about 1600 pounds and varying indiameter from about four feet up to about eight feet, are rapidlyreplacing the relatively smaller conventional square bales.

Due to the large size of the round bales, there is a need for equipmentwhich can pick up the bales in the field, accumulate a load of bales,and transport them to a remote storage area where the accumulated balescan be unloaded. Also, such equipment must be flexible in the ability todeal with bales ranging in diameter from the aforesaid four to eightfeet. Furthermore, it is important that the bale handling equipment beable to arrange and control the position of bales on the transporter bedafter the bales have been picked up. Transporting larger loads of balesreduces fuel usage and the time required for bale handling.

Currently known round bale handling equipment is limited in being ableto successfully pick up, accumulate, transport and unload large loads ofround bales, e.g., eight to ten bales, and cope with the varying balesize. Some equipment is available for handling large loads of bales butthis equipment is tractor drawn and is thus limited by tractor speed andreduced maneuverability. Other equipment available is self-propelled,such as a pickup truck attachment for handling large round bales. Whilethis other equipment avoids the speed and maneuverability limitations oftractor drawn equipment, it sacrifices the economic advantagesassociated with transporting a large number of bales.

The unloading of bales from the load bed of the bale wagon can beeffected by pivotally rotating the load bed relative to the main frame,thereby raising the forward end of the load bed above the frame, topermit the round bales to roll or slide off the rearward end of the loadbed. To impart sufficient energy to the bales on the load bed so thatthey will be easily discharged off the rearward end of the load bed, itwould be desirable to provide a mechanism, such as a tailgate, and acontrol system therefor that would prevent the bales from moving off theload bed until the forward end has been raised a sufficient distance offthe main frame.

SUMMARY OF THE INVENTION

It is an object of this invention to overcome the aforementioneddisadvantages of the prior art by providing a control system for atailgate that maintains the tailgate in an upright position to preventbales from being discharged off the rearward end of the load bed of around bale wagon until the forward end of the load bed has been raised asufficient distance to impart enough energy to the bales to enable themto be easily discharged off the rearward end.

It is another object of this invention to provide an actuation mechanismthat will allow the tailgate to move from an upright position to anextended position when the load bed has been rotated approximately 35degrees.

It is another object of this invention to provide an actuation mechanismthat will automatically effect a raising of the tailgate back into anupright position when the load bed has been returned to its homeposition substantially parallel to the main frame of the round balewagon.

It is still another object of this invention to provide an overloadrelief mechanism which would permit the tailgate to move from theupright position if the tailgate is overloaded.

It is a feature of this invention that the movement of the tailgate isautomatically effected by the movement of the load bed relative to themain frame.

It is an advantage of this invention that no operator input is necessaryto actuate the movement of the tailgate to allow bales to be dischargedfrom the load bed of the round bale wagon.

It is another advantage of this invention that the overload reliefmechanism reduces the chance of damage occurring to the tailgate.

It is a further object of this invention to provide a control system forautomatically actuating the tailgate on a round bale wagon, which isdurable in construction, inexpensive of manufacture, carefree ofmaintenance, facile in assemblage, and simple and effective in use.

These and other objects, features and advantages are accomplishedaccording to the instant invention by providing a control system for atailgate on a round bale wagon wherein the tailgate is maintained in anupright position to keep bales on the load bed of the vehicle until theforward end of the load bed has been raised sufficiently to impartenough energy to the bales to enable them to be more easily unloaded offthe rearward end of the load bed. The control system includes anactuation mechanism that is engageable with the main frame upon therotation of the load bed relative to the main frame to shift the spoolof a control valve to permit hydraulic fluid to escape from thehydraulic cylinder operatively powering the movement of the tailgate tothe upright position. The weight of the bales on the tailgate presentssufficient force to cause the tailgate to move to an extended positionand, thereby, extend the ram of the hydraulic cylinder, forcing fluidfrom the cylinder. Movement of the load bed back to the home position,generally parallel to the main frame, causes the spring loaded actuationmechanism to operatively disengage from the main frame and effect ashifting of the control valve spool to permit fluid to flow back to thehydraulic cylinder and effect a retraction of the ram and movement ofthe tailgate back into the upright position.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages of this invention will become apparent upon considerationof the following detailed description of the invention, especially whentaken in conjunction with the accompanying drawings wherein:

FIG. 1 is a top plan view of a round bale wagon incorporating theprinciples of the instant invention with portions broken away to revealthe hydraulic cylinders of the bale handling system;

FIG. 2 is a side elevational view of the round bale wagon seen in FIG. 1with portions broken away to highlight the locations of the hydrauliccylinders;

FIG. 3 is a somewhat simplified fragmentary plan view of the mobilechassis of the round bale wagon seen in FIG. 1 with the load bedremoved, revealing the control valves for the cylinders highlighted inFIGS. 1 and 2 and the mechanical linkages for actuating the controlvalves;

FIG. 4 is a cross-sectional view showing the single lever control forboth the hydraulic squeeze and lift functions of the pickup mechanismtaken along lines 4--4 of FIG. 3;

FIG. 5 is a cross-sectional view showing the control panel in the cab ofthe round bale wagon taken along lines 5--5 of FIG. 4;

FIG. 6 is an enlarged fragmentary plan view, corresponding to a portionof FIG. 3, with portions broken away to highlight the control linkagefor effecting an automatic cycling of the bale handling mechanisms, theover-center linkage being shown in its open position;

FIG. 7 is an enlarged fragmentary plan view corresponding to a portionof FIG. 6 and showing the over-center linkage in its closed position,with the open position being shown in phantom;

FIG. 8 is an elevational detail view corresponding to lines 8--8 of FIG.7 and showing the over-center linkage in its closed position;

FIG. 9 is an elevational detail view corresponding to FIG. 8 with theover-center linkage being shown in the open position, as taken alonglines 9--9 of FIG. 6, but on an enlarged scale;

FIG. 10 is an elevational detail view taken along lines 10--10 of FIG. 6and showing the control linkage that is actuated by the bale pickupmechanism;

FIG. 11 is an elevational detail view of the control linkage actuated bythe cross conveyor as taken along lines 11--11 of FIG. 6;

FIG. 12 is an elevational detail view taken along lines 12--12 of FIG. 6and showing the control linkage actuated by the bale pusher mechanism;

FIG. 13 is a fragmentary plan view of the cross conveyor showing thevalve for locking the cross conveyor in an inboard transport position;

FIG. 14 is a partial elevational view taken along lines 14--14 of FIG. 3and showing the control valve and linkage for automatically actuatingthe tailgate; and

FIGS. 15a and 15b are combinable halves of a schematic diagram of thehydraulic system of the round bale wagon seen in FIGS. 1 and 2, FIGS.15a and 15b being combinable along the dashed match line at the right ofFIG. 15a and on the left of FIG. 15b.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings and, particularly, to FIG. 1, a plan viewof a round bale wagon incorporating the principles of the instantinvention can be seen. Left and right references are used as a matter ofconvenience and are determined by standing at the rear of the machinefacing the forward end, the direction of travel. A general descriptionof the machine depicted in the drawings can be found in co-pending U.S.Ser. No. 161,719. This bale wagon is of the self-propelled type;however, the primary source of power and some of the drive mechanismhave been removed to simplify the drawing for purposes of clarity.

GENERAL STRUCTURE OF PREFERRED EMBODIMENT

The round bale wagon 10 is designed to pick up and transport large roundbales, such as processed by the apparatus disclosed in U.S. Pat. No.3,827,223. The round bale wagon 10 has the ability to function as anoff-highway agricultural vehicle capable of good maneuverability and lowspeed for picking up round bales, yet transport over the road from fieldto field. The round bale wagon 10, depicted in the drawings, can handleapproximately eight-six foot diameter round bales or 10-four footdiameter round bales.

The round bale wagon 10 includes a wheeled frame 11 on which is mountedan operator's cab 12, offset to the left side and at the forward end ofthe wagon 10 for good visibility during both operation and transport. Aload bed 20 includes a sub-frame 21 pivotally connected at pivot 22 tothe frame 11 and supporting a floor 23. The load bed 20 is provided withside rails 24 which are laterally adjustable to accommodate differentsized bales 14 and for minimizing the width of the wagon 10 duringtransport. A pair of hydraulic cylinders 26 operatively interconnect thewheeled frame 11 and the frame 21 of the load bed 20 to selectivelyeffect a pivotal movement of the load bed 20 about the pivot 22 relativeto the frame 11 to move the forward end 28 of the load bed 20 above theframe 11 and the rearward end 29 closer to the ground G for thedischarge of bales 14 from the load bed 20. The hydraulic cylinders 26are connected through hoses 27 to a hydraulic system that can beactuated by controls located in the cab 12, as will be described infurther detail later.

A load rack 30 is positioned at the forward end of the load bed 20 toprovide a means for guiding and retaining round bales 14 loaded thereon.The load rack 30 includes a forwardly positioned recessed cradle portion31 for receiving round bales 14 deposited thereon by the pickupmechanism 40 and for guiding round bales 14 conveyed by the crossconveyor means 60, as will be described below. The load rack 30 alsoincludes a raised planar portion 32 extending rearwardly from therecessed cradle portion 31 and terminating in an edge 33 raised abovethe floor 23 to form a stop 34 to prevent bales 14 positioned in row Bfrom moving forwardly and interfering with the positioning of bales 14in row A on the recessed cradle portion 31. A slot 36 is also providedin the load rack 30 for the operation of the pusher advance means 80,also further described below.

A bale pickup means 40 includes a subframe 42, which is pivotallyconnected at pivot 41 to the wheeled frame 11 adjacent the forward end28 of the load bed 20 and to the right of the cab 12. The bale pickup 40is pivotally movable in the fore-and-aft direction about pivot 41 and isoperable to pick up a round bale 14 lying on the ground G, and todeposit it in the recessed cradle portion 31 of the load rack 30immediately rearwardly thereof. The subframe 42 includes a cross member43 interconnecting two forwardly extending arms 44, 45. The cross member43 can be telescopically constructed so as to be selectively adjustableto vary the distance between the two forwardly extending arms 44, 45 toaccommodate various size bales 14.

The forwardly extending arm 44 is fixed with respect to the cross member43 and includes an enlarged pad-like member 47 for engaging asubstantially planar side of a round bale 14. The other forwardlyextending arm 45 is pivotally connected at pivot 46 to the cross member43 to be movable toward and away from the fixed arm 44. The pivotalmovement of the squeeze arm 45 is effected by a hydraulic cylinder 48,which is connected to the central hydraulic system by the hose 49. Thesqueeze arm 45 also includes a pad-like member 47 for engaging asubstantially planar side of a round bale 14.

A pair of hydraulic cylinders 51, connected to the central hydraulicsystem by the hose connection 52, operably interconnect the subframe 42of the bale pickup means 40 and the main frame 11 of the round balewagon 10 for pivotally moving the bale pickup means 40 between a pickupposition, seen in FIGS. 1 and 2, wherein a bale 14 is engaged betweenthe forwardly extending arms 44, 45 while still on the ground G, and aloading position, wherein the bale pickup means 40 deposits a round bale14 in the recessed cradle portion 31 in row A immediately rearwardly ofthe bale pickup means 40. The hydraulic cylinder 48 is operable topivotally move the squeeze arm 45 toward and away from the fixed arm 44so as to releasably squeeze a round bale 14 therebetween, enabling thebale pickup means 40 to pick up a round bale 14 off the ground G anddeposit it in the recessed cradle portion 31.

At the rearward end 29 of the load bed 20 a tailgate 55 is pivotallyconnected to the frame 21 of the load bed 20 at pivot 56. A hydrauliccylinder 58, connected to the central hydraulic system by means of thehose connection 59, is connected between the load bed 20 and thetailgate 55 and is operable to pivotally move the tailgate 55 between anupright position seen in FIG. 2, wherein the round bales 14 in row D areprevented from rolling off the load bed 20, and an extended position,not shown, wherein the round bales 14 are permitted to roll off the loadbed 20 over the tailgate 55. A further explanation of the function andoperation of the tailgate can be found below.

A cross conveyor means 60 is provided for laterally moving a round bale14 in a row A along the recessed cradle portion 31 from a positionimmediately rearwardly of the bale pickup means 40 to a positionimmediately rearwardly of the cab 12 and is described in greater detailin co-pending U.S. Ser. No. 187,012. In general, a linkage 62 pivotallyinterconnects the main frame 11 and a cross conveyor arm 64, which has aframe-like member 65 mounted thereon for engaging a round bale 14 andmoving it laterally along the recessed cradle portion 31. The crossconveyor means 60 is operatively powered by a hydraulic cylinder 68,that is in operative communication with the central hydraulic system viathe hose connection 69, and interconnects the main frame 11 and thecross conveyor linkage 62 to cause the frame-like member 65 to engage around bale 14 and move it laterally across the recessed cradle portion31 before returning to the outboard, home position.

The cross conveyor means 60 is provided with a retaining means 70, whichis operable to hold the cross conveyor arm 64 and attached frame-likebale engaging member 65 in a position inboard of the side rails 24, soas to reduce the overall width of the round bale wagon 10 duringtransport thereof over public roads. The retaining means 70 is depictedin FIGS. 1 and 13 in the form of a valve 72 in operative communicationwith the hose 69. The valve 72 seen in FIGS. 1 and 13 includes a manualshut off control 74; however, one skilled in the art will readilyrealize that other similar devices, such as a solenoid valve, could besubstituted. The valve 72 is operable to prevent the flow of hydraulicfluid through the hose 69 to or from the hydraulic cylinder 68 and,thereby, prevent the hydraulic cylinder 68 from pivotally moving thecross conveyor linkage 62. Accordingly, if the valve 72 is closed afterthe hydraulic cylinder 68 has moved the cross conveyor arm 64 andattached bale engaging member 65 inboard of the side rails 24, the crossconveyor means 60 will be locked at that inboard position to minimizethe transport width of the wagon 10.

A pusher advance means 80 is pivotally connected to the main frame 11 atpivot 81 and is operable to advance round bales 14 rearwardly from rowA, positioned in the recessed cradle portion 31, over the raised planarportion 32 of the load rack 30 to row B rearwardly thereof. The balepusher mechanism 80 includes a transverse pusher bar 82 fixed to asupport arm 84, which in turn is pivotally connected to the main frame11 at pivot 81. The transverse pusher bar 82 is of sufficient size toengage all of the round bales 14 in row A and advance them rearwardly torow B. Although not shown in the drawings, the transverse pusher bar 82can be constructed to be telescopically adjustable to accommodatevarious sized bales 14 being loaded into recessed cradle portion 31. Thepusher advance means 80 is operatively powered by a hydraulic cylinder88 interconnecting the main frame 11 and the support arm 84. Thehydraulic cylinder 88 is connected to the central hydraulic system bymeans of hose connections 89.

GENERAL OPERATION OF THE PREFERRED EMBODIMENT

In operation, the round bale wagon 10 is maneuvered over the groundsurface G until a round bale 14 is positioned between the forwardlyextending arms 44, 45 of the bale pickup means 40 with the planar endsof the cylindrical round bale 14 positioned adjacent to the respectiveforwardly extending arms 44, 45. The squeeze arm 45 is then pivotallymoved by manipulation of the hydraulic cylinder 48 until both the fixedarm 44 and the squeeze arm 45 have engaged the sides of the round bale14 and is squeezed therebetween. Manipulation of the hydraulic cylinder51 pivotally rotates the bale pickup means 40 until the bale 14 ispositioned in the recessed cradle portion 31 of the load rack 30immediately rearwardly thereof. Subsequent manipulation of the hydrauliccylinder 48 to move the squeeze arm 45 away from the fixed arm 44releases the round bale 14 and deposits it on the load rack 30.

After the round bale 14 has been deposited in the recessed cradleportion 31 of the load rack 30 rearwardly of the bale pickup means 40,the hydraulic cylinder 68 is manipulated to cause the cross conveyormeans 60 to laterally move the round bale 14 across the recessed cradleportion 31 from a position immediately rearwardly of the bale pickupmeans 40 to a position immediately rearwardly of the cab 12. Upon thereturn of the cross conveyor arm 64 and the attached bale engagingmember 65 to the outboard, home position, a second bale can be picked upby the bale pickup means 40 and deposited in the recessed cradle portion31, at which point, the recessed cradle portion 31 of the load rack 30would be filled.

A manipulation of the hydraulic cylinder 88 to effect a rotation of thesupport arm 84 about the pivot 81, causes the transverse pusher bar 82to engage the bales 14 in row A and advance them rearwardly over theplanar portion 32 of the load rack 30 until positioned in row B. Afterthe pusher advance means 80 has returned to its home position, as seenin FIGS. 1 and 2, the bale pickup means 40 can deposit another bale onthe recessed cradle portion 31 of the load rack 30 to initiate anothercycle to ultimately fill the recessed cradle portion 31 with round bales14 in row A. At this time the pusher advance means 80 is actuated againto advance the bales in row A rearwardly to row B, causing the bales 14previously in row B to move rearwardly to row C. This sequence isrepeated until all rows A, B, C and D are filled with round bales 14.

The bale wagon 10 is then driven to a selected storage area where theload of bales 14 is dumped by actuating the hydraulic cylinder 26 topivot the load bed 20 about the pivot 22. The tailgate 55 is preferablymaintained in the upright position seen in FIG. 2 until the forward end28 of the load bed 20 is sufficiently high above the frame 11 to impartsufficient energy to the bales 14 to allow them to easily slide or rolloff the floor 23 of the load bed 20. At this time, the hydrauliccylinder 58 is actuated to cause the tailgate 55 to pivotally move fromits upright position to an extended position and permit the round bales14 to freely move off the load bed 20.

Although the description above is directed to the drawings depicting aload of four rows of round bales 14 positioned two across in each row,one skilled in the art would readily realize that smaller or largersized bales 14 would likely result in more or less rows of bales.Furthermore, one skilled in the art should also realize that somemodification to the linkages and controls described herein could be madeto provide rows of bales having one, two or more bales in each row.

HYDRAULIC SYSTEM CONTROL LINKAGE

From the description of the operation of the bale wagon 10 above, itshould be noted that a number of hydraulically powered devicessequentially operate to fully load and subsequently discharge the loadbed 20 with round bales 14. Although end hydraulic cylinder having afunction in this sequential flow of events could have a separate controllever located in the cab 12 for manipulation by the operator, it isdesirable that a single control lever be used to operate all thehydraulic functions of the loading process. Accordingly, FIGS. 3 through13 depict a control linkage 90 for mechanically sequentially controllingthe lateral cross conveying of the bales 14 along the recessed cradleportion 31 of the load rack 30 and the rearward advance of the balesfrom the load rack 30 by the pusher advance means 80 in conjunction withthe raising and lowering of the bale pickup means 40.

Referring now to FIGS. 3, 4, 5 and 6, a partial cross sectional view ofthe bale wagon 10 through the cab 12 and beneath the load bed 20 toreveal the hydraulic control linkage 90 can be seen. Each respectivehydraulic cylinder 26, 48, 51, 58, 68 and 88 has a separate controlvalve connected by hoses 27, 49, 52, 59, 69 and 89, respectively, tocontrol the operation thereof. Control valve 91 is connected tohydraulic cylinder 26 via hose 27 to control the tilting of the load bed20 about the pivot 22. Control valve 93 is connected to hydrauliccylinder 48 via hose 49 to control the manipulation of the squeeze arm45.

Control valve 95 is connected to hydraulic cylinder 51 via hoses 52 tocontrol the lifting of round bales 14 from the ground G to deposit themon the recessed cradle portion 31 of the load rack 30 via the pivotalrotation of the pickup subframe 42 about the pivot 41. Control valve 96is connected to hydraulic cylinder 58 via hose 59 to control theoperation of the tailgate 55. Control valve 97 is situated within thehydraulic circuit to effect a delay of the operation of the crossconveyor means 60 until the bale pickup means 40 has rotated forwardly asufficient distance to prevent interference therebetween. Control valve99 is operable to control the operation of both the cross conveyor means60 and the pusher advance means 80 via a sequential manipulation ofhydraulic cylinders 68 and 88, as will be described in further detailbelow.

A single lever 100 is located within the cab 12 for control of both thelift and squeeze functions of the bale pickup means 40. Lever 100 isrotatably mounted upon shaft 101 and extends upwardly through a slot 102having quadrants n, l, o, c and r in a control panel 103 within the cab12. A connecting link 105 interconnects the control lever 100 with across link 106 interconnecting control valves 93 and 95. As best seen inFIG. 4, the valves 93 and 95 are mounted on the main frame 11 in aspaced relationship to one another. The connecting link 105 is connectedto the cross link 106 at a point closer to valve 93 than to valve 95.Accordingly, manipulation of the lever 100 will effect a movement of thespool 93a in a control valve 93 before effecting a movement of spool 95ain control valve 95 when moving from the neutral position.

Referring again to FIGS. 3, 4 and 5, movement of the lever 100 from theneutral position at quadrant 102-n to quadrant 102-o would cause acorresponding movement of the control link 105 and effect a movement ofspool 93a and operate the hydraulic cylinder 48 to move the squeeze arm45 away from the fixed arm 44. A further movement of lever 100 toquadrant 102-l would finally effect a movement of spool 95a andmanipulate the hydraulic cylinder 51 and lower the bale pickup means 40into a position to engage a bale 14 on the ground G. As can be seen inFIG. 15 and as described in further detail below, movement of spool 95afrom its neutral position to either its innermost or outermost positionshuts off the flow of fluid to control valve 93 and "freezes" thehydraulic cylinder 48 in whatever position it is in until spool 95a isreturned to the center, neutral position, whereupon fluid flow returnsto valve 93 for manipulation of hydraulic cylinder 48.

A subsequent movement of the lever 100 to quadrant 102-c would firstreturn spool 95a to its neutral position, then return spool 93a to itsneutral position, by virtue of the spring loading of valve spools 93aand 95a, and finally effect a movement of the spool 93a to cause ahydraulic cylinder 48 to move the squeeze arm 45 toward the fixed arm 44and clamp or squeeze a bale 14. A further movement of lever 100 toquadrant 102-r would then effect movement of spool 95a to cause thehydraulic cylinder 51 to rotate the subframe 42 of the bale pickup means40 about the pivot 41 and deposit the clamped bale 14 in the recessedcradle portion 31 of the load rack 30. Movement then of lever 100 toquadrant 102-o would again cause movement of spools 93a and 95a, asnoted above, to manipulate hydraulic cylinder 48 and release the bale 14and start another cycle for the bale pickup means 40.

Referring now to FIGS. 3 and 5, control lever 110 is also rotatablymounted on shaft 101 and extends upwardly through a slot 112 havingquadrants 112-n, 112-l and 112-r in the control panel 103. Control lever110 is connected through links 114 directly to valve 91, such that amanipulation of the lever 110 between quadrants 112-n and 112-l or 112-rwill cause a movement of the spool 91a to effect the operation ofhydraulic cylinder 26 to pivotally rotate load bed 20 about pivot 22 andlower and raise, respectively, the forward end 28 to dump the load ofthe bales 14 therefrom.

Control lever 115 is pivotally mounted to the cab 12 and extendsupwardly through a slot 117 in the control panel 103. Control lever 115is connected via a connecting link 118 directly to a double selectorvalve 119, whose sole function is to divert hydraulic fluid to or fromthe control valves noted above. Movement of control lever 115 to thestop position as seen in FIG. 5., causes the valve 119 to divert oilfrom the pump directly back to the reservoir without being circulated toany of the valves noted above. Further reference can be made to FIGS.15a and 15b, wherein a schematic diagram of the hydraulic system isshown.

AUTOMATIC CONTROL LINKAGE

Referring now to FIGS. 3 and 6, the control linkage 120 forautomatically manipulating the movements of the cross conveyor means 60and pusher advance means 80 can be seen. Manipulation of the controlvalve 99 to selectively effect operation of the hydraulic cylinders 68and 88 is controlled through the movements of the pickup subframe 42about the pivot 41 when the bale pickup means 40 alternates between alowered bale pickup position and a raised bale loading position.

As can be best seen in FIGS. 6 and 10, a trip 122 is rotatably connectedto pivot 41 and is movable independently of the pickup subframe 42. Astop 123 mounted on the main frame 11 limits the amount of movement ofthe trip 122 in a forward direction. A connecting link 125 is connectedto the trip 122 and extends rearwardly therefrom through a mountingbracket 126 for connection to the spool 97a of delay valve 97. A spring127 biases the connecting link 125 to urge the trip 122 in a forwarddirection against the stop 123. Connecting link 125 is shown in FIG. 6to be of a known two piece construction with spring 128 providingprotection for valve 97 in case the connecting link 125 is movedrearwardly further than the spool 97a can move.

When the bale pickup means 40 rotates rearwardly to deposit a bale 14 onthe load rack 30, the pickup subframe 42 rotates about pivot 41 andcauses the subframe member 129 to engage the trip 122. Further rotativemovement of the subframe 42 rearwardly causes the cross member 129 tomove the trip 122 rearwardly, as best seen in FIG. 10, and effect acorresponding movement of the connecting link 125. This movementprovides for the sequential operation of both the cross conveyor means60 and the pusher advance means 80 through the associated linkages andvalves as further described below.

The automatic linkage 120 includes a first link 131 pivotally connectedat one end at pivot 132 to the main frame 11 and at point 133intermediate its ends to the spool 99a for actuation thereof between apusher mode and a cross conveyor mode. The first link 131 is pivotallyconnected at pivot 134 to a second link 135. The second link 135 isconnected to both the spool 97a and the connecting link 125 at point 136intermediate its ends. As can best be seen in FIGS. 8 and 9, the secondlink 135 has a free end 137 that projects through a guide slot 138 in abracket 139 to be engageable with an over-center mechanism 140.

The over-center mechanism 140 is best seen in FIGS. 6-9. In general, thefunction of the over-center mechanism 140 is to control the movement ofthe free end 137 of the second link 135, which in turn controls theactuation of the control valve 99 between the pusher and cross conveyormodes, as will be described in detail below. A fixed stop 142 ispositioned adjacent the guide slot 138 of the bracket 139 so as torestrict the movement of the free end 137 of the second link 135 in arearward direction. The fixed stop 142 is depicted in the drawings inthe form of a bolt 143 adjustably mounted in a bracket 144.

The over-center mechanism 140 is rotatably mounted about an axis definedby the shaft 145. A movable stop 147 is fixedly attached to the shaft145. A movable stop 147 is fixedly attached to the shaft 145 androtatable therewith between an open position 148, as seen in FIGS. 6 and9, in which the movable stop 147 is spaced somewhat from the free end137 of the second link 135, and a closed position 149, as seen in FIGS.7 and 8, in which the movable stop 147 is positioned adjacent to thefree end 137 of the second link 135 to trap it against the fixed stop142 and prevent it from moving within the guide slot 138.

An over-center link 151 is pivotally connected at pivot 152 to themovable stop 147 and also connected at the opposing end 153 to a spring154. The spring 154, which is attached to the main frame 11, biases themovable stop 147 from either side of the axis of rotation defined by theshaft 145, depending upon the position of the over-center link 151. Whenthe movable stop 147 is in the open position 148, the spring 154 urgesthe movable stop 147 toward the open position 148 by reason that theline of force exerted by the spring 154 passes to the right of the shaft145. When the movable stop 147 is moved into the closed position 149,the line of force exerted by the spring 154 is to the left of the shaft145 and, therefore, urges the movable stop 147 into the closed position149. The over-center link 151 is curved to permit the line of forceexerted by the spring 154 to be positioned on either side of the shaft145 depending upon the position of the movable stop 147. The bracket 139and the elongated member 156 serve as limits to the amount of movementof the movable stop 147 between the open position 148 and the closedposition 149.

To actuate the movement of the movable stop 147 from the open position148 to the closed position 149, a first actuating means 160 operativelycommunicates between the over-center mechanism 140 and the crossconveyor linkage 62. A first arm 162 is affixed to the shaft 145 androtatable therewith, so that there is no relative movement between thefirst arm 162 and the movable stop 147. A first actuating link 163pivotally interconnects the first arm 162 and a first trip means 165.

The first trip means 165 is best seen in FIGS. 6, 11 and 13 and includesan elongated pivot bar 166 pivotally connected to a bracket 167 mountedon the main frame 11. The pivot bar 166 is connected to the firstactuating link 163 by a pin 168 that rides within the lost motion slot164. The spring 161 biases the pivot bar 166 in a counterclockwisedirection, as viewed in phantom in FIG. 6. The pivot bar 166 furtherincludes a trip pin 169 projecting from the plane of the pivot bar 166for engagement with a trip arm 66 connected to the cross conveyorlinkage 62. Although the operation of the first actuating means 160 willbe described in further detail below, the trip arm 66 engages the trippin 169, when the cross conveyor means 60 returns to the outboard, homeposition after conveying a round bale 14 along the recessed cradleportion 31, to pivotally rotate the pivot bar 166 in a counterclockwisedirection, as seen in FIG. 6, and cause a corresponding movement of thefirst actuating link 163 to the right and, therefore, rotate theover-center mechanism 140 and place the movable stop 147 in the closedposition 149.

To actuate the movement of the movable stop 147 from the closed position149 to the open position 148, a second actuating means 170 is provided.The second actuating means 170 is best seen in FIGS. 6, 7, 8, 9 and 12.A second arm 172 is affixed to the shaft 145 and rotatable therewith,such that there is no relative movement between the second arm 172 andthe movable stop 147. A second actuating link 173 pivotallyinterconnects the second arm 172 and a second trip means 175.

The second trip means 175 includes a pivot link 176 pivotally connectedto a bracket 177 mounted on the main frame 11. The pivot link 176 isconnected to the second actuating link 173 by a pin 178 riding withinthe lost motion slot 174 in the link 173. The pivot link 176 furtherincludes a trip pin 179 projecting from the pivot link 176, so as to beengageable with a trip arm 86 affixed to the pusher advance means 80.Although the operation of the second actuating means will be describedin further detail below, in general, the trip arm 86 engages the trippin 179 when the pusher advance means 80 returns to the forward, homeposition and effects a forward movement of the second actuating link 173to rotate the over-center mechanim 140 so as to move the movable stop147 from the closed position 149 to the open position 148.

OPERATION OF THE CONTROL LINKAGES

To initiate the operation of the round bale wagon 10 to pick up roundbales 14 lying on the ground G and load them on the load bed 20, themechanism described above must by cycled so that the bale engagingmember 65 on the cross conveyor arm 64 of the cross conveyor means 60 ispositioned at its outboard, home position to the right side of the loadbed 20 and the pusher advance means 80 is positioned such that thepusher bar 82 is at its rearwardmost position, while the bale pickupmeans 40 is in a pickup position adjacent the ground G ready to engage around bale 14. The round bale wagon 10 is then guided so that the pickupmeans is positioned adjacent the first bale 14 to be loaded with thefixed arm 44 and the squeeze arm 45 adjacent opposing substantiallyplanar sides of the cylindrical round bale 14.

The operator would then move the control lever 100 to slot quadrant102-c to actuate the control valve 93, through the connecting link 105and cross link 106, as described above, and cause the hydraulic cylinder48 to move the squeeze arm 45 toward the fixed arm 44 and firmly engagethe round bale 14 therebetween. The operator would then move the controllever 100 to slot quadrant 102-r whereby the control valve 95 would beactuated to cause the hydraulic lift cylinders 51 to rotate the pickupframe 42 about the pivot 41 and, thereby, raise the engaged round bale14 to a position in the recessed cradle portion 31 of the load rack 30immediately rearwardly of the bale pickup means 40.

As will be seen through the description of the sequential cycling of thelinkage as found below, the starting position described above wouldresult in the over-center mechanism 140 being positioned such that themovable stop 147 is in its closed position 149. As the pusher advancemeans 80 returns to its home position, as described above with respectto FIG. 12, the trip arm 86 engages the second trip means 175 to causethe second actuating link 173 to move forwardly, rotating theover-center mechanism 140 about the shaft 145 and positioning themovable stop 147 into the open position 148.

As the frame 42 of the bale pickup means 40 rotates upwardly about thepivot 41, as described above with respect to FIG. 10, the subframemember 129 engages the trip 122 and causes the connecting link 125 tomove rearwardly. Since the free end 137 of the second link 135 islimited in its rearward movement by the fixed stop 142, the entirelinkage 120, including the first link 131 and the second link 135,pivots about the free end 137 of the second link 135, thereby pushingboth spools 97a and 99a inwardly. Although the operation of thehydraulic system is described in further detail below, this inwardmovement of spool 99a causes the control valve 99 to shift into thecross conveyor mode.

When the frame 42 of the bale pickup means 40 is rotated downwardlyabout pivot 41, the biasing spring 127 causes the connecting link 125 tomove forwardly until the trip 122 engages the stop 123. Since themovable stop 147 of the over-center mechanism 140 has been moved intothe open position 148 by the operation of the second actuating means170, the free end 137 of the second link 135 is free to slide forwardlywithin the guide slot 138 of the bracket 139. As a result, the spool 97aof the delay valve 97 is pulled into its outward position and the secondlink 135 pivots about the connection 134 without affecting any movementof the first link 131 or the spool 99a. Valve 97 is operable to delaymovement of the cross conveyor means 60 when the spool 97a is in itsinward position until the pickup means 40 has rotated forwardly out ofinterference with the frame-like member 65 and, thereby, moving thespool 97a to its outermost position to permit the hydraulic cylinder 68to be actuated.

Since the control valve 99 is in the cross conveyor mode, for thereasons described below with respect to the description of the hydraulicsystem, the hydraulic cylinder 68 retracts to cause the bale engagingmember 65 on the cross conveyor arm 64 to engage the bale 14 positionedwithin the recessed cradle portion 31 by the bale pickup means 40 andslide it across the load rack 30 to a position immediately rearwardly ofthe cab 12. When the over-center mechanism 140 was rotated to cause themovable stop 147 to move to its open position 148, the first actuatinglink 163 of the first actuating means 160 was pulled to the left suchthat the pin connection 168 with the first actuating link 163 waspositioned at the right end of the lost motion slot 164. Accordingly,when the cross conveyor means 60 slides the bale 14 across the recessedcradle portion 31, the trip arm 66 engages the trip pin 169 to pivotallymove the pivot bar 166 and slide the pin 168 within the lost motion slot164 without causing any movement to the first actuating link 163. Afterthe trip arm 66 has moved past the trip pin 169, the biasing spring 161returns the pivot bar 166 to a position where the pin 168 is againlocated at the right end of the lost motion slot 164.

When a second bale 14 has been engaged by the bale pickup means 40between the fixed arm 44 and the squeeze arm 45, the hydraulic liftcylinders 51 are again actuated to cause the pickup frame 42 to rotateupwardly about the pivot 41. As will be described below with respect tothe description of the hydraulic system, the positioning of spool 95a tocause the hydraulic lift cylinders 51 to rotate the bale pickup means 40upwardly automatically causes the cross conveyor means 60 to return toits outboard, home position with the frame-like bale engaging member 65along the right side of the load bed 20.

The movement of the cross conveyor linkage 62 to its home positioncauses the trip arm 66 to engage the trip pin 169 and pivotally rotatethe pivot bar 166 in a counterclockwise direction, as viewed in FIG. 6,thereby causing the pin 168 to move the first actuating link 163 to theright to rotate the over-center mechanism 140 so that the movable stop147 is positioned in the closed position 149. As described above, theupwardly rotative movement of the pickup frame 42 about the pivot 41causes the subframe member 129 to engage the trip 122 and move theconnecting link 125 rearwardly, causing the spool 97a to move to itsinward position. Since the spool 99a is already in its inward positionand, therefore, in the cross conveyor mode, movement of the spool 99awould not be affected.

After the second bale 14 has been deposited in the recessed cradleportion 31 of the load rack 30 by the bale pickup means 40, the spool95a is manipulated to cause the hydraulic lift cylinders 51 to rotatethe pickup frame 42 downwardly about the pivot 41. As the pickup frame42 rotates downwardly, the biasing spring 127 pushes the connecting link125 forwardly until the trip 122 engages the stop 123. Since the freeend 137 of second link 135 is now trapped between the fixed stop 142 andthe movable stop 147, the forward movement of the connecting link 125causes the second link 135 to pivot about its free end 137, therebycausing the pivotal connection 134 between the first link 131 and thesecond link 135 to move forwardly and, therefore, pivot the first link131 about its pivotal connection 132 with the frame 11 and move thespool 99a outwardly so as to shift the control valve 99 into the pushermode.

As will be described in further detail below, the movement of thecontrol valve 99 to the pusher mode and the disengagement of the delayvalve 97 permits the hydraulic cylinder 88 to be actuated, causing thepusher advance means 80 to move the round bales 14 from row A to row B.When the over-center mechanism 140 was rotated to position the movablestop 147 in its closed position 149, the second actuating link 173 wasmoved rearwardly such that the pin 178 connecting the second actuatinglink 173 with the pivot link 176 is at the forward end of the lostmotion slot 174. The movement of support arm 84 rearwardly about thepivot 81 causes the trip arm 86 to engage the trip pin 179 and rotatepivot link 176 rearwardly. However, the pin 178 is free to moverearwardly within the lost motion slot 174 until the trip arm 86 isdisengaged from the trip pin 179; whereupon, the pivot link 176 is freeto rotate by gravity until the pin 178 is again at the forward end ofthe lost motion slot 174 for subsequent engagement by the trip arm 86 tomove the second actuating link 173 forwardly and rotate the over-centermechanism 140. At this point, the bale wagon 10 is at the startingposition as described above. Further recycling of the events enumeratedabove will finally result in the load bed 20 being filled with roundbales 14.

STRUCTURE AND OPERATION OF THE TAILGATE

Once the load bed 20 is filled with round bales 14, the wagon 10 isdriven to a selected location where the bales 14 are to be stored. Toempty the load of bales from the load bed 20, the operator moves thecontrol lever 110 to slot quadrant 112-r and, thereby, moving theconnecting link 114 forwardly to shift the spool 91a of the controlvalve 91 and actuate the hydraulic cylinders 26 and rotate the frame 21to the load bed 20 about its pivotal connection 22 with the main frame11, raising the forward end 28. It should be noted that a hydraulicinterlock is provided so that the forward end 28 of the load bed 20cannot be raised unless both the cross conveyor 60 and the pusheradvance means 80 are cycled to their respective home positions and thebale pickup means 40 is lowered to a position where the pusher advancemeans 80 just begins to move rearwardly.

It is desirable that the tailgate 55 remains in its upright positionwith respect to the load bed 20, as seen in FIG. 2, until the load bed20 is positioned at an approximate 35 degree angle with respect to themain frame 11, at which time the tailgate 55 should release to permitthe round bales 14 to slide and/or roll off. Referring now to FIGS. 2, 3and 14, the actuating mechanism 180 for automatically releasing thetailgate 55 from its upright position can be seen.

The actuating mechanism 180 includes a bracket 182 mounted to the frame21 of the load bed 20 to be movable therewith and supporting the controlvalve 96 which is mounted thereon. An actuating link 184 interconnectsthe spool 96a and a pivot link 185, which is pivotally mounted on theload bed frame 21. The actuating link 184 is of a two piececonstruction, similar to the connecting link 125, and includes both abiasing spring 187 and a protection spring 188, as well as beingpivotally connected to the pivot link 185. The biasing spring 187pivotally rotates the pivot link 185 forwardly into engagement with thestop 186. The pivot link 185 also includes a trip member 189 affixedthereto and extending for engagement with the main frame 11.

In operation, when the hydraulic cylinders 26 are actuated to cause theforward end 28 of the load bed 20 to rotate upwardly, the trip member189 engages the main frame 11 and causes the pivot link 185 to rotaterelative to the frame 21 of the load bed 20. As a result, the actuatinglink 184 ultimately shifts the spool 96a to actuate the hydrauliccylinder 58 and rotate the tailgate 55 about its pivotal connection 56with the load bed 20. The length of the actuating link 184 and theposition of the trip member 189 relative to the frame 11 permit thespool 96a to shift and, thereby, actuate the hydraulic cylinder 58, whenthe load bed 20 has been raised to an angle of approximately 35 degreesrelative to the main frame 11. Retaining the tailgate 55 in its uprightposition until the load bed 20 has been raised to approximately thispoint prevents the bales 14 from moving until they have sufficientheight to freely and easily move off the load bed 20.

HYDRAULIC SYSTEM

Referring no to FIGS. 15a and 15b, a somewhat simplified schematicdiagram of the hydraulic system for the round bale wagon 10 can be seen.Valves 91, 93 and 95, operating the load bed 20, the squeeze arm 45 andthe pickup means 40, respectively, have three position spools and arespring loaded to the central, neutral position. Valves 96 and 97,corresponding to the tailgate 55 and the delay for the cross conveyormeans 60, respectively, are shown as having three position spools whichare spring loaded to be biased in one direction only. Valves 99 and 119need only have two position spools, without any spring bias, so as to beonly externally actuatable. Hydraulic cylinders 26, 48, 51, 58, 68 and88 are schematically shown in FIG. 15b. It should be noted that FIGS.15a and 15b are combinable along a match line located along at the rightof FIG. 15a and at the left of FIG. 15b.

The central hydraulic system 200 includes a reservoir 202 containing asupply of hydraulic fluid and a pump 204 which places the fluid underpressure through the inlet line 203 as the primary source of power forthe components in the hydraulic system 200. A flow divider 206 drawsfluid from the inlet line 203 to provide power for an assortment ofhydraulically powered devices, such as power steering, which arediagrammatically shown as being housed in box 207. A return manifold 209collects the hydraulic fluid after being circulated and returns it tothe reservoir 202 to complete the circuit.

Hydraulic fluid flows initially through line 211 to the double selectorvalve 119. The position of the valve spool 119a is manually controlledby the operator through manipulation of control lever 115 and connectinglink 118. If the valve spool 119a is shifted out, the oil flows fromport 119b to port 119f and directly back to the return manifold 209without being circulated to any of the other valves. When the valvespool 119a is shifted in, as depicted in FIG. 15a, the oil flow fromport 119b to port 119c and then onwardly through line 213, after passingthrough a pressure check 214, to port 95b of valve 95. Simply stated,the double selector valve 119 operates only to divert the flow ofhydraulic fluid to or away from the remaining valves.

When the valve spool 95a is in the central, neutral position, fluidflows into port 95b and back out port 95c and through line 215 to port93b of valve 93. When valve 93 is in the central, neutral position,fluid flows into port 93b and back out port 93c and onward through line217 to port 91b of valve 91. When valve spool 91a is in the central,neutral position, fluid flows into port 91b and back out port 91cthrough line 219 to port 119d, then through valve spool 119a, out port119e and through line 221 back to the return manifold 209. It is fromthis basic flow pattern tht the various hydraulic cylinders areoperated.

It should be noted that, with reference to FIG. 4, movement of theconnecting link 105 in either a forward or rearward direction willalways actuate valve 93 before actuating valve 95; however, because bothvalve spools 93a and 95a are spring loaded to the central, neutralposition, valve spool 93a will not shift from an extreme inward positionto an extreme outward position until both valve spools 95a and 93a havemoved to the central, neutral position. For example, when control lever100 is in slot quadrant 102-n both valve spools 93a and 95a are in theneutral position. When control lever 100 is shifted to slot quadrant102-c, valve spool 93a is shifted to the innermost position to operatehydraulic cylinder 48 through lines 216 and 218, while valve spool 95aremains in the neutral position. As noted above and further describedbelow, hydraulic fluid will not flow to valve 93 unless valve spool 95ais in the neutral position. Accordingly, when control lever 100 isshifted from slot quadrant 102-r back to 102-n valve spool 95a moves tothe central, neutral position, followed by valve spool 93a moving to thecentral, neutral position, at which time hydraulic fluid can flow on tothe hydraulic cylinder 48 through the valve 93 because valve 95 is thenin the neutral position.

With reference to the starting position as enumerated above, the balepickup means 40 has been lowered with the pusher advance means 80 in itsrearwardmost position. Control lever 100 is positioned in slot quadrant102-c shifting the valve spool 93a to its innermost position and causinghydraulic fluid to flow from port 93b to port 93d and onwardly to thehydraulic cylinder 48 to extend it and move the squeeze arm 45 towardthe fixed arm 44. Movement of control lever 100 to slot quadrant 102-rshifts spool 95a to its innermost position to cause hydraulic fluid toflow from port 95b to port 95d and onwardly through lines 220 to thehydraulic lift cylinders 51 to cause extension thereof and rotate thesubframe 42 about the pivot 41.

Hydraulic fluid leaving hydraulic cylinders 51 flows through line 223 tothe cross connection 224. The fluid then flows through line 222 toretract the hydraulic cylinder 88 because of the flow path available atthe cross connection 224, line 222 presenting the path of leastresistance. Hydraulic fluid leaving hydraulic cylinder 88 through line225 proceeds to the T connection 226 and becomes divided to flow throughboth lines 227 and 229. Hydraulic fluid flowing through line 229ultimately returns back to port 119d of valve 119, exiting port 119e andreturning via line 221 to the return manifold 209. Hydraulic fluidflowing through line 227 enters port 99f of valve 99 and exits port 99b,because valve 99 has been positioned in its outermost position, which isthe pusher mode, via the automatic linkage 120.

Hydraulic fluid will then flow from port 99b to a pressure relief valve230 via line 231 and back to port 95e via line 233, whereupon the flowexits valve 95 at port 95f, then flows through line 235 to line 219 andultimately back to the return manifold 209. Once the hydraulic cylinder88 has been completely retracted, fluid flowing from the crossconnection 224 through the line 222 builds up sufficient pressure toopen the relief valve 240 to permit the fluid to flow through line 237and back to the return manifold 209.

It should be noted that the block valve, as labeled at the bottom ofFIG. 15b, has no specific function other than to house a multitude ofcheck valves, orifices, relief valves, a flow divider and T connections.These various hydraulic parts would normally have individual housingsand be distributed throughout the system; however, it has been found tobe convenient to house them in one central location. It has been foundthat with an open center hydraulic system, as depicted in FIGS. 15a and15b, having a pump that will deliver a flow of 30.5 gallons per minuteto provide a pressure of 2,000 pounds per square inch along line 211 tothe double selector valve 119, setting the relief valve 230 at 1,900pounds per square inch provides relief for the system when either thecross conveyor means 60 or the pusher advance means 80 has been advancedto its respective extreme position by the hydraulic cylinder 68 and 88,respectively, while setting the relief valve 240 at 1,000 pounds persquare inch provides adequate relief for the system when either thecross conveyor means 60 or the pusher advance means 80 reaches therespective home position.

With regard to the operation of valve 97 to effect a delay in theoperation of the cross conveyor means 60, it should be noted thatwhenever the connecting link 125 has been moved rearwardly by theengagement between member 129 and the trip 122, thereby shifting spool97a to its innermost position, the valve spool 95a is necessarily at itsinnermost position to effect an extension of the hydraulic cylinders 51.Hydraulic fluid is flowing from the double selector valve 119 to port95b and exiting port 95e to travel through line 233 to relief valve 230.The flow of hydraulic fluid continues from the relief valve 230 throughline 231 to port 99b, exiting port 99c, because the automatic linkage120 always shifts valve spool 99a to its innermost position when theconnecting link 125 is moved rearwardly, to flow through line 239 andline 241 to port 97b of the delay valve 97, due to the positioning ofthe check valve 242.

By exiting the fluid through port 97c, the delay valve diverts hydraulicfluid away from hydraulic cylinder 68 through line 243 into the blockvalve and back out through line 223 to the hydraulic cylinders 51 tocause retraction thereof and lower the bale pickup means 40. Fluidleaving the hydraulic cylinders 51 returns through the line 220 to port95d, exiting port 95f, because the valve spool 95a has been shifted toits outermost condition by the control lever 100 being positioned inslot quadrant 102-l, to travel through line 235 to line 219 and back tothe return manifold 209 through valve 119.

Once the bale pickup means 40 has been lowered to a position whereby thevalve spool 97a is shifted to its outermost position, hydraulic fluidarriving at valve 97 through line 241 enters port 97b and exits port 97dto flow through line 245 into a flow diverter 246 located in the blockvalve. The flow diverter 246 permits fluid to flow through line 247 andthe manual shut-off valve 72 to the hydraulic cylinder 68 to cause aretraction thereof and actuate the cross conveyor means 60 to slide abale 14 across the recessed cradle portion 31.

Hydraulic fluid leaving the hydraulic cylinder 68 returns over lines 244and 223 to the hydraulic cylinders 51, to continue operation thereof tolower the bale pickup means 40, and ultimately back to the returnmanifold through lines 220, 235, 219 and 221. The flow diverter 246 alsopermits hydraulic fluid to flow directly to the hydraulic cylinders 51over line 248, through the cross connection 224 and line 223. Hydraulicfluid can pass through line 249 to line 237 and back to the returnmanifold 209 to relieve pressure in line 247 when there is no flow inline 244. When the hydraulic cylinder 68 has reached the end of itsretraction stroke, the relief valve 230 opens to permit hydraulic fluidto flow directly from line 233 to line 248 and via line 223 to the liftcylinders 51.

The hydraulic cylinders 26 for pivotally raising the forward end 28 ofthe load bed 20 can only be actuated through valve 91 when both valves93 and 95 are in the central, netural position and the interlockselector valve 99 has its spool 99a positioned at its outermostposition, the pusher mode. Hydraulic fluid entering valve 91 via line217 from valve 93 enters port 91b and exits port 91d, by reason thatvalve spool 91a has been moved to its outermost position throughplacement of the control lever 110 in slot quadrant 112-r. Fluid exitingtoward 91d flows through line 251 into port 99d, exiting port 99e, byreason that valve 99 is in the pusher mode, and travels through line 238to hydraulic cylinders 26 to cause extension thereof.

Fluid leaving the hydraulic cylinders 26 through line 253 arrives at theT connection 254, where the flow enters port 91e. Fluid entering port91e exits port 91c and is returned to the return manifold 209. Reliefvalve 250 provides for a return of the hydraulic fluid from cylinder 58to line 219 and ultimately the return manifold 209, if cylinder 58becomes overloaded.

As the forward end 28 of the load bed 20 is raised and the tailgateactuating mechanism 180 shifts the spool 96a partially inwardly,hydraulic fluid entering port 96b exits port 96d and travels throughline 255 to line 219 and ultimately the return manifold 209, the fluidentering port 96c is blocked off to maintain pressure to the hydrauliccylinder 58. When the load bed 20 has reached approximately a 35 degreeangle with respect to the main frame 11, the valve spool 96a is shiftedto its innermost position to permit hydraulic fluid to escape thehydraulic cylinder 59 through line 252 to enter port 96c and exit port96d and ultimately to the return manifold 209, the pressure exerted onthe tailgate 55 by the round bales 14 providing sufficient power forextending the hydraulic cylinder 58.

When the control lever 110 is positioned in slot quadrant 112-l, thespool 91a is shifted to its innermost position to cause a reversing ofthe flow of hydraulic fluid through lines 253 and 238 and cause aretraction of the hydraulic cylinder 26. When the load bed 20 hasreached a position with respect to the main frame 11 that the tailgateactuating mechanism 180 permits the spool 96a to reach its outermostposition, hydraulic fluid reaching the T connection 254 from the valveport 91e can enter port 96b and exit port 96c to travel through line 252and effect a retraction of the hydraulic cylinder 58 and reposition thetailgate 55 in its upright position.

It will be understood that changes in the details, material, steps andarrangement of parts which have been described and illustrated toexplain the nature of the invention will occur to and may be made bythose skilled in the art upon a reading of this disclosure within theprincipals and scope of the invention. The foregoing descriptionillustrates the preferred embodiments of the invention. However,concepts, as based upon such description, may be employed in otherembodiments without departing from the scope of the invention.Accordingly, the following claims are intended to protect the inventionbroadly as well as in the specific form shown herein.

Having thus described the invention, what is claimed is:
 1. In a balewagon for picking up bales of crop material from the field, accumulatinga plurality of bales and transporting the accumulated bales to apreselected storage location to be unloaded from the bale wagon, thebale wagon having a mobile frame adapted for movement across the field;a bale pickup means mounted on said frame for individually engagingbales of crop material on the ground and elevating said bales onto thebale wagon; a load bed pivotally supported by a pivot on said frame foraccumulating a plurality of said bales, said load bed including aforward end, a rearwardly spaced rearward end and a receiving portion atsaid forward end on which said bale pickup means deposits bales pickedup on the field; means for arranging and positioning bales deposited onsaid load bed by said bale pickup means; and power means for arrangingand positioning said bales on said bale wagon and for selectivelyrotating said load bed about said pivot relative to said mobile frame toraise said forward end and unload bales accumulated thereon over saidrearward end, the improvement comprising:a tailgate pivotally connectedto said load bed at said rearward end and movable between an uprightposition, generally perpendicular to said load bed to prevent saidaccumulated bales from moving off said rearward end of said load bed,and an extended position, wherein said accumulated bales are permittedto move off said rearward end; tailgate power means for pivotally movingsaid tailgate from said extended position to said upright position, saidtailgate power means being operable to releasably maintain said tailgatein said upright position and including a hydraulic cylinder having a ramslidingly extendable therefrom between a retracted state when saidtailgate is in said upright position and an extended state when saidtailgate is in said extended position, said hydraulic cylinderinterconnecting said load bed and said tailgate and being in operativecommunication with a primary source of power for powering the movementof said tailgate, said hydraulic cylinder being connected to a controlvalve having a spool that permits hydraulic fluid to flow to saidhydraulic cylinder for retraction of said ram, said control valve spoolalso being operable to permit hydraulic fluid to escape from saidhydraulic cylinder when said ram is extending due to the weight of theaccumulated bale being exerted against the tailgate after said load bedhas been rotated to raise said forward end of said mobile frame; andactuating means operatively connected with said tailgate power means tocause said tailgate power means to permit said tailgate to move to saidextended position, said actuating means being operable when said forwardend of said load bed has been raised a predetermined distance above saidmobile frame to impart sufficient energy to said accumulated bales topermit them to move easily off said rearward end of said load bed. 2.The bale wagon of claim 1 wherein said actuating means includes a pivotlink pivotally connected to said load bed and having a trip endengageable with said mobile frame when said load bed is rotated aboutthe pivotal connection with said mobile frame and an actuation linkinterconnecting said pivot link and said control valve spool, said tripend engaging said mobile frame to pivotally rotate said pivot linkrelative to said load bed and actuate said control valve spool throughsaid actuation link to permit hydraulic fluid to flow from saidhydraulic cylinder.
 3. The bale wagon of claim 2 wherein said actuationlink is spring loaded to bias said control valve spool toward theposition where hydraulic fluid is permitted to flow into the hydrauliccylinder, said control valve spool being in the position where fluid ispermitted to escape from said hydraulic cylinder through said controlvalve after said pivot link has engaged said mobile frame to overcomethe spring bias in said actuation link and effected a shifting of saidcontrol valve spool.
 4. The bale wagon of claim 3 wherein said tailgatepower means includes an overload relief valve to permit hydraulic fluidto escape from said hydraulic cylinder without passing through saidcontrol valve should said tailgate be subjected to an overload of weightexerted thereon.
 5. The bale wagon of claim 4 wherein said actuatingmeans shifts said control valve spool to the position where hydraulicfluid is permitted to escape from said hydraulic cylinder through saidcontrol valve when said forward end of said load bed has been raised toa position wherein the load bed is at an angle of approximately 35degrees relative to said mobile frame.
 6. In a bale wagon for picking upbales of crop material from the field, accumulating a plurality of balesand transporting the accumulated bales to a preselected storage locationto be unloaded from the bale wagon, the bale wagon having a mobile frameadapted for movement across the field; a bale pickup means mounted onsaid frame for individually engaging bales of crop material on theground and elevating said bales onto the bale wagon; a load bedpivotally supported by a pivot on said frame for accumulating aplurality of said bales, said load bed including a forward end, arearwardly spaced rearward end and a receiving portion at said forwardend on which said bale pickup means deposits bales picked up on thefield; means for arranging and positioning bales deposited on said loadbed by said bale pickup means; and power means for operatively poweringsaid bale pickup means, said means for arranging and positioning saidbales on said bale wagon and for selectively rotating said load bedabout said pivot relative to said mobile frame to raise said forward endand unload bales accumulated thereon over said rearward end, theimprovement comprising:a tailgate pivotally connected to said load bedat said rearward end and movable between an upright position, generallyperpendicular to said load bed to prevent said accumulated bales frommoving off said rearward end of said load bed, and an extended position,wherein said accumulated bales are permitted to move off said rearwardend; a hydraulic cylinder interconnecting said load bed and saidtailgate to pivotally move said tailgate from said extended position tosaid upright position, said hydraulic cylinder being in operativecommunication with a primary source of power and including a ramslidably extendable therefrom, said ram being retracted when saidtailgate is in said upright position and extended when said tailgate isin said extended position; a control valve operatively connected to saidhydraulic cylinder and having a spool that permits hydraulic fluid toflow to said hydraulic cylinder for retraction of said ram, said controlvalve spool also being operable to permit hydraulic fluid to escape fromsaid hydraulic cylinder when said ram is extending due to the weight ofthe accumulated bales being exerted against the tailgate after said loadbed has been rotated to raise said forward end of said mobile frame; andactuating means operatively connected to said control valve foractuating said spool to permit hydraulic fluid to escape from saidhydraulic cylinder only after said forward end of said load bed has beenraised a predetermined distance above said mobile frame to impartsufficient energy to said accumulated bales to permit them to moveeasily off said rearward end of said load bed.
 7. The bale wagon ofclaim 6 wherein said actuating means includes a pivot link pivotallyconnected to said load bed and having a trip end engageable with saidmobile frame when said load bed is rotated about the pivotal connectionwith said mobile frame and an actuation link interconnecting said pivotlink and said control valve spool, said trip end engaging said mobileframe to pivotally rotate said pivot link relative to said load bed andactuate said control valve spool through said actuation link to permithydraulic fluid to flow from said hydraulic cylinder.
 8. The bale wagonof claim 7 wherein said actuation link is spring loaded to bias saidcontrol valve spool toward the position where hydraulic fluid ispermitted to flow into the hydraulic cylinder, said control valve spoolbeing in the position where fluid is permitted to escape from saidhydraulic cylinder through said control valve after said pivot link hasengaged said mobile frame to overcome the spring bias in said actuationlink and effected a shifting of said control valve spool.
 9. The balewagon of claim 8 wherein an overload relief valve is operativelyconnected to said hydraulic cylinder to permit hydraulic fluid to escapefrom said hydraulic cylinder without passing through said control valveshould said tailgate be subjected to an overload of weight exertedthereon.
 10. The bale wagon of claim 9 wherein said actuating meansshifts said control valve spool to the position where hydraulic fluid ispermitted to escape from said hydraulic cylinder through said controlvalve when said forward end of said load bed has been raised to aposition wherein the load bed is at an angle of approximately 35 degreesrelative to said mobile frame.
 11. A bale wagon for picking up roundbales of crop material from a field, accumulating a plurality of roundbales and transporting the accumulated round bales to a preselectedstorage location to be unloaded from the bale wagon, comprising:a mobileframe adapted for movement across the field; a bale pickup means mountedon said frame for individually engaging said round bales on the groundand elevating said round bales on the bale wagon; a load bed pivotallysupported on said frame for accumulating a plurality of said roundbales, said load bed having a forward end, a rearwardly spaced rearwardend and a tailgate pivotally connected to said rearward end and movablebetween an upright position being generally perpendicular to said loadbed to prevent said accumulated bales from moving off the rearward endof said load bed and an extended position wherein said tailgate does notrestrict the movement of said bales off said rearward end; means forarranging and positioning round bales deposited on said load bed by saidbale pickup means; power means for operatively powering said bale pickupmeans, said means for arranging and positioning and for selectivelypivotally rotating said load bed relative to said frame to raise saidforward end and unload bales accumulated thereon off said rearward end;tailgate power means for pivotally moving said tailgate from saidextended position to said upright position, said tailgate power meansbeing operable to releasably maintain said tailgate in said uprightposition, said tailgate power means including a hydraulic cylinderinterconnecting said tailgate and said load bed and having a ramslidingly extendable therefrom, said ram being retracted when saidtailgate is in said upright position and extended when said tailgate isin said extended position, said hydraulic cylinder being connected to acontrol valve having a spool movable between first and second positions,said first position of said spool permitting hydraulic fluid to flow tosaid hydraulic cylinder for retraction of said ram, said second positionof said spool permitting hydraulic fluid to escape from said hydrauliccylinder to permit the extension of said ram due to the weight of saidaccumulated bales being exerted against said tailgate after said loadbed has been rotated to raise said forward end of said mobile frame,actuating means operatively connected to said tailgate power means tocause said tailgate power means to permit said tailgate to move fromsaid upright position to said extended position, said actuating meansbeing operable when said forward end of said load bed has been raised apredetermined distance above said frame to impart sufficient energy tosaid accumulated bales to permit them to easily move off said rearwardend, said actuating means being operatively connected to said spool andeffecting movement of said spool to said second position when theforward end of said load bed has been raised said predetermineddistance.
 12. The bale wagon of claim 11 wherein said actuating meansincludes a pivot link pivotally connected to said load bed and having atrip engageable with said mobile frame when said load bed is rotatedabout the pivotal connection with said mobile frame and an actuationlink interconnecting said pivot link and said control valve spool, saidtrip end engaging said mobile frame to pivotally rotate said pivot linkrelative to said load bed and cause said actuation link to move saidcontrol valve spool to said second position to permit said tailgate tomove to said extended position.
 13. The bale wagon of claim 12 whereinsaid actuation link is spring loaded to bias said control valve spooltoward said first position, said control valve spool being in saidsecond position after said pivot link has engaged said mobile frame toovercome the spring bias in said actuation link and effected a shiftingof said control valve spool.